GDSII Layer Mapping

When you import a GDSII file, the translator reads the layer information from the GDSII file, then populates this page with the stream information. You edit the settings to provide the correct mapping of the GDSII Stream file to the Sonnet project.

The various fields are described below. The first two columns refer to the incoming GDSII file. The last four columns are the choices to be used in the Sonnet project editor for the GDSII elements identified in the first two columns.

The Layer Mapping page of the Import Wizard allows you to map the GDSII  streams to the Sonnet project levels on import. The settings on this page are also used to automatically create Technology Layers during the import.

When the Layer Mapping page is opened, the settings are populated either using default settings determined by reading the GDSII file or by reading the settings in a template project. By default, if no other source of mapping is provided, the project editor assigns each "on" GDS stream to a unique Sonnet planar metal level.  If you are using a template project, the layers are mapped using the import/export mapping settings of the technology layers in the template file. No matter the source for the initial settings in the Layer Mapping page, you may edit all the settings and apply those changes before importing the GDSII file.

The various fields are described below. The first two columns refer to the incoming GDSII stream in the GDSII file you are importing. The last four columns are the choices to be used in the Sonnet project editor for the GDSII stream identified in the first column.

GDSII Stream: The stream layer number as defined in your circuit layout program. Note that the stream layer number has no relationship to the project editor’s metalization level number.

GDSII Data Type: The data type number as defined in your circuit layout program. Each stream layer, defined by your circuit layout program, may have multiple data types. Different data types in a stream may be mapped to different Sonnet metal layers.

Map: Use this checkbox to select which stream layers in the GDSII file you wish to map to the Sonnet project. If this checkbox is off, the GDSII stream layer is not mapped to the Sonnet project and the icon is displayed. If the checkbox is on, then the GDSII stream layer and data type in the first two columns are mapped to a Technology Layer, object type, level and material type specified in the last four columns and the icon is displayed. If you wish to map all the layers, select the checkbox at the top of the column under the rightward pointing arrow. Clearing this checkbox deselects all layers from mapping.

Tech Layer: Enter a name to identify the Technology Layer which is created in the resulting Sonnet project when your circuit is translated. If you do not wish to create a Technology Layer for the stream, select "None" from the drop list. A default name is automatically entered by the software but you may edit the entry and enter a custom name if you desire. The object type, level and material used by the Tech Layer are determined by the selections made in the Object Type, Level and Material columns.

If you are importing to a project that contains Technology Layers, the Technology Layers fields are filled in by default, based on the properties of the Tech Layer. For any row which is set to a pre-existing Tech Layer, the Project Editor fields (Object type, Level, and Material) will be fixed to the values set by the corresponding Tech Layer, and may not be changed.

Object Type: This drop list allows you to select what type of object should be created in the Sonnet project. Select Metal for planar metal polygons, Brick for dielectric bricks or Via for via polygons from the drop list. You select or enter the metal type or brick material from the Material drop list. If a Technology Layer is being created, this selection also determines the Technology Layer type: Metal, Brick or Via.

Level: This specifies the level in the Sonnet project where you wish to place the specified data type from the stream layer being input from the GDSII file. If a Technology Layer is being created, it is assigned to this level.  The top level is number 0. For via conversion, you input a range of levels. For example, a via which extends from level 2 upwards to level 0 would be 2-0. A via extending from level 3 to ground would be 3-GND. A via extending from level 3 up to the top cover would be 3-TOP. Note that the project editor creates enough metal levels in the destination project to accommodate any levels entered in this field. For example, if a via level of 2-6 is input, the project will have at least 8 levels (0-GND).

Material: Select the material type you wish to use for the objects being translated. The choices available depend on what type of object is selected in Object type: Metal, Via, or Brick and what materials are available in the template project, if one is being used. You may also edit this entry with a new material name, whose parameters you can later input in the project editor. If a Technology Layer is being created, this is the Material used for the Technology Layer.

For example, if you are importing a GDSII file into a project with four defined types of planar metal, you may choose from those four planar metal types for any metal polygons being translated into the Sonnet project.

: Click on this button to add another entry row. Additional rows allow you to map a single GDSII stream to multiple Technology Layers, object types, levels, and/or materials.

: Click on this button to delete the presently selected row in the dialog box.

: Click on this button to load the settings from an existing layer file with mapping settings for the GDSII file you are importing.

: Once the mapping is specified, you may wish to save the settings for subsequent imports of similar GDSII files. Click on the Save button to save your settings in a file. It is recommended that you use a ".lay" extension which is the default.

Note:  It is normally preferable to use a template file for your imports since more information may be included in a template file than in a layer file. The .lay file is maintained for backward compatibility.

Next: Click on the Next button to continue the import GDSII process. The GDSII translator opens the Import Options page of the Import Wizard.